diff --git a/dockerfiles/Dockerfile.test b/dockerfiles/Dockerfile.test
index 4938691..9cf0d4e 100644
--- a/dockerfiles/Dockerfile.test
+++ b/dockerfiles/Dockerfile.test
@@ -12,6 +12,7 @@ RUN apt-get update && apt-get install -y \
     libffi-dev \
     libmbedtls-dev \
     chicken-bin
+RUN chicken-install r7rs
 RUN git clone https://gitea.scheme.org/Retropikzel/compile-r7rs.git --depth=1
 RUN cd compile-r7rs && make && make install